CH660586A5 - DEVICE FOR CONTROLLING THE BREMSAUSLOESEPUNKTES in elevators. - Google Patents

Abstract

1. Equipment, for the control of the braking initiation point in lifts, with markings (M1, M4), which are applied in the lift shaft (14) at a certain spacing from the storeys and which co-operate with a switch (15), which is actuable when the lift cage (6) travels past, and with a speed-measuring equipment (1) connected with the hoist motor (1), wherein the braking initiation point is determinable in dependence on the speed measured when the lift cage (6) travels past the marking (M1, M4) of the target storey and wherein stopping errors of earlier travels are taken into consideration in the determination of the braking initiation point, characterised thereby, - that a distance table (RAM1) is provided in the form of a store, in which the distances between the markings (M1, M4) of each storey are stored, - that a computer (RE) is provided, which from the distances forms a target travel (SSoll ) respectively associated only with the storey concerned and which determines a braking initiation travel (SEinl ) through subtraction of an empirical braking travel (SBr ) from the target travel (SSoll ), - that a travel counter (C3) is provided, which is started when the lift cage (6) travels past the first marking (M1) of a storey and on the signal change of the switch (15) brought about thereby, and - that a comparator (KO) is provided, which on equality of the travel counter state and the braking initiation travel (SEinl ) generates a signal determining the braking initiation point.

Description

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PATENT CLAIMS pulse generator (26), a timing device (CPU) and a

1.Means for controlling the brake trigger point at speed register (C4), the time between elevators, measured in the elevator shaft (14) in a particular two adjacent pulses of the pulse generator (26), distance from the floors made markings their reciprocal value and for an adaptive filter (Ml, M4), which cooperate with a switch (15) which can be actuated as the instantaneous speed in the speed control (6) when the elevator car 5 is passing, and which is stored with a ster (C4).

with the lifting motor (1) connected speed measuring device. 10. Device according to claim 9, characterized in

direction, the braking trigger point depending on that the pulse generator (26) consists of a reflective film (27)

when the elevator car (6) drives past the marking and a reflective light barrier (28), the reflective film

(Ml, M4) of the target floor measured speed io (27) on a swing coupled with the lifting motor (1)

can be determined, and being fixed when determining the brake release disk (7) and reflecting and non-reflecting

points of stopping errors from previous journeys are considered.

characterized,

- That a distance table (RAMI) in the form of a memory

is provided in which the distances between the markers 15

rungen (Ml, M4) of each floor are stored, The invention relates to a device for controlling the

- That a computer (RE) is provided which, from the Distan brake trigger point for elevators, with in the elevator shaft in zen forms a desired distance (SSoI1) attached to the respective floor and assigned a certain distance from the floors, and by subtracting one from the Markings, which interact with a brake path (SBr) derived from the target path (SSou) 20 bine that can be actuated when the lift ka experience passes, and with a speed measuring device connected to a brake initiation path (SEinl), which is connected to the lifting motor,

- That a path counter (C3) is provided, the brake trigger point depending on when driving the elevator car (6) past the mark (Ml) when the elevator car passes the mark on the target floor and the result of this caused signal change floor measured speed can be determined, and the switch (15) is started, and 25 where stopping errors when determining the brake trigger point

- That a comparator (KO) is provided, which is taken into account in earlier trips.

the travel counter reading and the brake initiation distance (SEini) for elevators of simple design and small nominal travel

generates a signal determining the brake release point. speed, the nominal driving speed can also during

2. Device according to claim 1, characterized by the passage of the smallest floor distance, net that a further marking per floor and direction of travel 30 In such elevators, the braking phase during the preparation (M2, M3) is provided, which is arranged at a smaller distance from the elevator car on a floor level attached in the elevator shaft, a first, a second marking, for example in the form of a magnet, being inserted and a third distance (D1, D2, D3) between all the markings , whereby the markings are always formed at the same distance from gen (Ml, M2, M3, M4) of a floor. the floors are arranged. This type of brake introduction

3. Device according to claim 2, characterized gekennzeich- leads to inaccuracies, mainly due to the net that the target path (SSoli) from the sum of the first distance with the cabin load changing load moments and (Dl) and half of the second distance ( D2) is formed. hence the driving speed.

4. Device according to claim 2, characterized gekennzeich- With the CH-PS 392 004, a control device is known net that the target path (SSoii) from the sum of the first distance, by means of which from the aforementioned green (Dl) and first distance (Dl) divided by the ratio 40 the resulting inaccuracies are avoided solder first distance (Dl) to half the second distance (D2) len. For this purpose, a tachometer dynamo is used. one proportional to the travel speed of the elevator car

5. Device according to claim 2, characterized marked voltage generated, which is provided via a relay and one of the net that a switchable from the first and third distances (D1, D3) elevator car switch of a reference voltage, DO the setpoint 45 is countered. Here, the reference voltage generated by a stabilized (SSolI) from the sum of the mean value (DO) and the mean value voltage source is greater than the (DO) divided by the ratio of the first distance (Dl) to the greatest tachometer voltage. Half of the second distance (D2) is formed on the stabilized chip. a capacitor and resistors are

6. Device according to claim 2, characterized in that the capacitor network when the switch is closed, that the voltage stored in the distance table (RAMI) is equal to the reference voltage. Distances (D1, D2, D3) in the elevator shaft are counter readings of the travel counter (C3), markings are arranged for each direction of travel at a certain distance from those on repeated repetitions of the elevator car (6). The floors can be corrected when driving past. the elevator car at the marking of the destination floor

7. Device according to claim 1, characterized in that the switch is opened so that the capacitor discharges itself via the net that a braking distance table (RAM2) 55 in the form of a memory 55 resistors. If the capacitor voltage is provided to the value pairs in which the speed / braking level of the tachometer voltage has dropped, the relay drops out, being stored away, which are derived from a value pair measured the first time the drive motor is switched off and the brake braking, which comes to mind. Depending on the magnitude of the tachometer voltage, the stored braking distances will sooner or later become zero after the results of further braking voltage at the relay, so that a solution can be corrected. 60 control of the time dependent on the driving speed

8. Device according to claim 1, characterized thereby the brake release is achieved.

net that a floor correction table (RAM3) in the form of a case with one known from DE-AS 1096 574

Memory is provided, in which floors with special equipment for fine adjustment of elevators, correction values (KSt) are stored at the ren friction conditions. Elevator cabin control contacts are arranged, by means of which there can be detected 65 stopping errors when calculating the brake initiation distance (SEini). With the help of the

can be added to the braking distance (SBr). contacts, a step switch can be operated, which

9. The device according to claim 1, characterized in that it is designed in such a way that it is proportional to the size of the net that the speed measuring device, from a stopping error, has a resistor arranged in the brake circuit.

stand can adjust. The stopping error stored in this way now has an effect on the next trip in such a way that a more or less large current flows in the braking circuit, as a result of which a new stopping error is to be avoided.

In a further apparatus for stopping an elevator car, which has become known from DE-OS 3 038 873, instead of the capacitor discharge described in CH-PS 392 004, the brake triggering time is calculated by means of a microprocessor as a function of the speed, the underlying equation merely provides approximate results. To improve the results, similar to DE-AS 1096 574, stopping errors from previous trips are taken into account in the calculation. This is done in such a way that after each trip the difference between the target and actual braking distance is used to calculate the brake release time that would have been required for precise stopping. This point in time is stored together with the speed measured at a shaft marking when the elevator car drives past. On the following journeys, the pairs of values determined in this way are also taken into account when calculating the braking release time.

The object underlying the invention is to further improve the holding accuracy in lifts of the type mentioned. To achieve this object, the invention proposes to record the shaft marking -floor level, which fluctuates due to construction tolerances from floor to floor, and to specify them as target paths for a path-dependent determination of the braking trigger point, the braking trigger point being derived from the difference between the respective target path and one derived from experience Braking distance is determined.

The advantage achieved with the invention can be seen in particular in the fact that the stopping accuracy is significantly increased by the precise detection of the distances between the shaft marking and the floor level and the path-dependent determination of the braking trigger point. The stopping accuracy is further improved by generating, storing and storing correction values for floors with different friction ratios and taking them into account when calculating the brake trigger point. Another advantage is that the device according to the invention can be retrofitted into already existing elevator systems of various types without having to carry out complex adjustment and adjustment work on the existing installations.

The invention is explained in more detail below with reference to an exemplary embodiment shown in the drawing. Show it:

Figure 1 is a schematic representation of an elevator with the inventive device for controlling the brake release point.

FIG. 2 shows an entry section defined by manhole markings, on a larger scale than in FIG. 1;

3 shows a diagram of the speed curve during the braking phase at full load downward and full load upward without using the device according to the invention, and

Fig. 4 is a diagram illustrating the speed profiles of Fig. 3 when using the inventive device.

In FIG. 1, 1 denotes the lifting motor of an elevator, which drives a elevator car 6 suspended on a conveyor cable 4 and balanced by means of a counterweight 5 via a gear 2 and a traction sheave 3. The lifting motor 1, for example an asynchronous motor, is coupled to a flywheel 7 and the brake drum 8 of an electromechanical holding brake and is connected to a three-phase network RST via contacts 9, 10 of directional protection devices 11, 12 and contacts 13 of a main switch. The control of the direction of travel contactors 11, 12 is assumed to be known and therefore

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not shown and described. The elevator car 6 is guided in an elevator shaft 14, which may extend over twelve floors E1-E12, for example, and in which four markings in the form of magnets M1-M4 are arranged at a certain distance from the floors. A bistable magnetic switch 15 is fastened to the elevator car 6 and is actuated when the elevator car 6 drives past the magnets M1-M4 and is electrically connected to an input of a control device 16 described in more detail below. Floor relays SP1-SP12 are assigned to floors E1-E12, which can be controlled by means of floor call transmitters DE1-DE12 provided on floors E1-E12 and car call transmitters (not shown) arranged in elevator car 6. With SK1-SK12 self-holding contacts are designated, via which the floor relays SP1-SP12 keep voltage after entering calls. The self-holding contacts SK1-SK12 are connected to a conductor 17, via which the storey relays SP1-SP12 are switched off in a known manner after the execution of a travel command by means of switching elements (not shown). The floor relays SP1-SP12 are connected to further inputs of the control unit 16 in order to query their memory status.

18 with a magnetic coil of the electromechanical holding brake is designated, which is connected to a voltage source, not shown, via a contact 20 of a brake relay 19 while the elevator car 6 is traveling. The brake relay 19 is connected on the one hand to a pole of the voltage source and on the other hand to an output of the control unit 16 and to a control relay 21. The contactors 11, 12 can be controlled via a contact 22 of the control relay 21 in such a way that the lifting motor 1 is switched off when the brake is applied. A brake contact 23 which can be actuated by the holding brake and is closed when the elevator car 6 is at a standstill is connected to a further input of the control unit 16. In order to ensure that no calls can be entered while driving, the floor call transmitters DE1-DE12 are connected to the voltage source via another brake contact 24, which is also only closed when the vehicle is at a standstill. A contact 25 of a directional contactor 11 is connected to a further input of the control unit 16 for the purpose of reporting the direction of travel.

A pulse generator 26 consists of a reflective film 27 attached to the flywheel 7 and a reflective light barrier 28 which is connected to a further input of the control device 16. The reflective film 27 has reflective and non-reflective zones, the zones being distributed around the circumference of the flywheel 7 in such a way that one pulse each corresponds to a travel path of the elevator car 6 of, for example, 2 mm.

The control unit 16 consists of a distance table RAMI, a braking distance table RAM2, a floor correction table RAM3, a selector C1 indicating the respective cabin position, a floor register C2 indicating a destination floor, a distance counter C3, a speed register C4, a computer RE and a comparator KO. Distance, braking distance and floor correction table RAM 1, RAM2, RAM3 are read-write memories, while the selector C1, the floor and speed registers C2, C4 and the travel counter C3 are registers of a microprocessor CPU, the arithmetic unit of which functions the computer RE and of the comparator KO. The random access memories RAMI, RAM2, RAM3, the microprocessor CPU, a read-only memory EPROM and an interface circuit IF are connected to one another via a bus B consisting of data, address and control lines and, together with a clock generator T, form a microcomputer. The interface circuit IF can, for example, consist of a multiplexer for the data input from the floor relays SP1-SP12 and for the input and output of the other data from bus drivers which can be operated using a

3rd

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

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Address decoder can be activated. The output of the control unit 16 connected to the brake and control relay 19, 21 is connected to the corresponding output of the interface circuit IF via a switch 29, for example in the form of a transistor switch.

The distances between the magnets M1-M4 of each floor are stored in the distance table RAMI, the distances in the downward travel direction of the elevator car 6 being denoted by first, second and third distances D1, D2, D3 (FIG. 2), and for example the first and the third distance D1, D3 40 cm each and the second distance D2 20 cm. The magnets M1-M4 are arranged in the elevator shaft 14 in such a way that when the elevator car 6 is flush with one floor, the magnetic switches 15 are located exactly in the middle of the second distance D2 (point III, FIG. 2).

The distance table RAMI is formed as follows:

While the elevator car 6, for example moving downward, drives past the magnets M1-M4, the input assigned to the magnetic switch 15 is queried by the control device 16. When the first signal change caused by the first magnet M1 occurs, the travel counter C3 is incremented as a function of the pulses generated by the pulse generator 26. With the second signal change, the counter reading is read and stored in the distance table RAMI under an address which is assigned to the floor number displayed by the selector C1 as the value of the first distance DL.

At the third signal change, the first distance D1 is subtracted from the counter reading and the difference is stored as the value of the second distance D2. In a similar manner, the value of the third distance D3 is determined and stored during the fourth signal change and the counter reading is then deleted. After the fourth signal change, the selector C1 is switched to the number of the next floor. If the vehicle drives past the same floor repeatedly, the existing values are compared with the newly determined values and corrected in the event of deviations. In addition, from the values of the distances D1 and D3 of the floors already traveled over, the mean value DO assigned to all floors is formed and stored.

In the braking distance table RAM2, braking distances SBr and the speeds associated with them, measured when the braking is initiated, are stored for each direction of travel. The braking distance table RAM2 is formed when braking for the first time, with further value pairs being formed based on the braking distance that has occurred and the assigned speed. This is done in such a way that in a range of, for example, 75-125% of the measured speed, the braking distances that increase with the speed and are derived from the first measured braking distance are determined and stored. After further journeys, these braking distances SBr are compared with the braking distances that have actually occurred and are corrected appropriately in the event of deviations.

The speed of the elevator car 6 required to use the braking distance table RAM2 is determined as follows:

Shortly before the braking is initiated (point I, FIG. 2), the time between two pulses of the pulse generator 26 is measured and its reciprocal value is formed. This value, which corresponds to the current elevator speed, is transferred to the speed register C4 after adaptive filtering. The time interval between the pulses of the pulse generator 26 can be measured, for example, by counting the pulses of the clock generator T, the first pulse of the pulse generator 26 occurring after the measurement command being called up starting a further counter of the microprocessor CPU and the following pulse stopping this counter.

Since the frictional conditions may not be the same over the entire elevator shaft 14, it can happen that the braking distance actually occurring is not the same on all floors at a certain speed. This can lead to a table value of the braking distance table RAM2, which has already been corrected several times, being falsified on floors with different friction. As a result, the stopping accuracy on the other floors deteriorates again, so that the corrections would have to be carried out again. To avoid this, the braking distance SBr stored in the braking distance table RAM2 is supplemented by a correction value KSt stored in the floor correction table io RAM3 and dependent on the direction of travel. The correction value KSt is formed in such a way that, depending on whether the braking distance error on a floor with a different friction is positive or negative, the correction value KStum is increased or decreased by one travel pulse, but does not exceed a maximum size.

When the elevator system is started up for the first time, the car position is determined during a learning trip and written into the selector C1. During further journeys 20, the distance, braking distance and floor correction table RAMI, RAM2, RAM3 are formed until the stored values have sufficient accuracy. The mode of operation of the device set and prepared in this way for determining the brake trigger point is explained below with reference to FIGS. 1 and 2:

It may be assumed that the elevator car 6 receives a travel command and starts to move downward from the floor Ell. When passing the fourth magnet M4 on the floor Ell, the selector Cl is switched to 30 floors E10. The control unit 16 then scans the inputs connected to the floor relays SP1-SP12, a call for floor E10 being stored, for example, so that the assigned floor number is transferred to the destination floor register C2. While driving, the input connected to the pulse generator 26 is activated and the current speed is continuously determined. When a value that no longer changes significantly is reached, it is transferred to the speed register C4 as already described above. A program for determining the brake trigger point is then called up, initially a brake initiation path SEini according to the relationship

Ssnl = Ssoll-Sß-Kst

_ is calculated. Herein, SSoll is one of the first and second 43 distances D1, D2 of the distance table RAMI according to the relationship

Ssoii - Tue +

D2

target path thus formed, which corresponds to the path that the elevator car 6 would have to travel from the first magnet M1 to the exact stop (point III, FIG. 2). If a floor is approached for the first time, the setpoint SSou is calculated based on the relationship Dl = 2-D2 chosen according to the example

Ssoii - Dq +

Dn

60

In the case of a tailgate plant or if a floor has not yet been traveled over and therefore the value of the distance D2 has not yet been saved, the desired path SSou is calculated using the ratio Dl = 2-D2 selected, for example, after the relationship

Ssoii - Tue +

Tue

The distances D1, D2, DO are called up from the distance table RAMI and the correction value KSt from the floor correction table RAM3 at an address which is assigned to the floor number contained in the selector C1, and taking into account the travel direction queried at the corresponding input of the control unit 16. The braking distance SBr is called from the braking distance table RAM2 at an address which is dependent on the speed stored in the speed register C4 and the direction of travel.

After the calculation, the brake initiation path SEini is stored and the input of the control device 16 connected to the magnetic switch 15 is activated. When the first signal change caused by the first magnet M1 of the floor E10 occurs, the travel counter C3 is incremented as a function of the pulses generated by the pulse generator 26. The distance counter reading is now continuously compared with the brake line path CSEj „i. If the paths and a stop determination are identical, which is given, for example, by the same floor numbers in the selector C1 and destination floor register C2, the output of the control unit 16 connected to the transistor switch 29 is activated such that the brake relay 19 and the control relay 21 drop out, the braking process

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triggered and the engine is switched off (point II, Fig. 2). The now closing brake contact 23 signals the brake application via the assigned input to the control device 16, as a result of which the floor number 5 contained in the destination floor register C2 is deleted. If the speed counter is zero, the distance counter is read and the actual braking distance is determined by subtracting the brake initiation path SEi „i. Then, as already described above, the correction of the braking distance table RAM2 is carried out.

In Fig. 3, vd denotes a speed curve at full load downward and vu one at full load upward. The brake is triggered at time t0 and starts to react at time t0. The path difference s resulting in the assumed extreme cases corresponds to the maximum stopping difference that occurs.

In contrast to FIG. 3, according to FIG. 4, the brake is only triggered at full load upward at time t '. The response time of the brake therefore shifts to the time t [. The initially occurring path difference Si is compensated for by a later occurring path difference s2 in the opposite direction, so that there is practically no stop difference.

M

2 sheets of drawings